The present invention relates to a device for indicating photographic exposure conditions.
There have been devised and demonstrated camera finder systems through which one can view a light-emitting element such as a light-emitting diode or the moving pointer of an ammeter which display an exposure condition. Since the light-emitting element or the moving pointer appears together with the image of an object, one tends to view the image of an object more intensely than the light-emitting diode or moving pointer, so that one very frequently neglects the warning given by the latter. As a result, erratic exposures or over- or under-exposures frequently result. This erratic exposure problem is inherent to the prior art finder system through which one must view the image of an object and a display device independently.
There has been also devised and demonstrated a finder system (See Japanese Utility Model Publication No. 10982/1980) of the type in which a ground glass has a liquid-crystal pattern or window. If exposure conditions are satisfactory, in response to the output signal from detection means for detecting exposure conditions, the liquid-crystal pattern is rendered transparent so that the image of an object can be viewed, but if exposure conditions are not satisfactory, the liquid-crystal pattern glass is rendered opaque so that the pattern is visible but the image of an object cannot be observed totally and consequently one is given the warning that the exposure conditions are not satisfactory. However, the image of an object is always focused upon the ground glass and the liquid-crystal pattern vanishes only when the object is sharply focused on the ground glass. In addition, the liquid-crystal pattern generally appears at the center of the ground glass. Therefore, the image of an object and the liquid-crystal pattern are mixed, so that one very frequently misses the liquid-crystal pattern. As a result, out-of-focus frequently results.